This invention relates to a fluidic power amplifier to amplify a driving force which is derived from a setting motor and which is applied to the spindle of a mechanism to be controlled, such as a linear setting drive.
In electric and electronic control systems frequently a setting motor is required which converts an electric information with high precision to a mechanical motion. Such motors conventionally have a small torque which in most cases is smaller than the torque requirement of the device to be controlled. To obtain such a required torque, it is known to interpose a linear or rotary power amplifier between the setting motor and the device to be controlled.
A linear power amplifier generally comprises a control valve which serves for the control of the flow of hydraulic fluid which effects an amplification of the torque of the setting motor by means of a fluidic pressure, as well as a threaded spindle with a spindle nut threadedly mounted thereon, whose position on the spindle is to be varied. A rotary power amplifier is in principle of similar construction except that instead of a spindle-and-nut assembly a simple driven shaft is used.